1. Technical Field
The present invention relates to a technique for rendering characters.
2. Related Art
Font data expressing a shape of a character is used to render the character to be presented on a display screen or to be printed on a paper sheet. Font data can be roughly divided into three types, e.g., a bitmap type, outline type, and stroke type. For example, in case of drawing a character using font data of the outline type, there are required three processing steps which are: “contour drawing” for rendering contours (character shape) of a character; “fill-in painting” for rendering the inside of the contours; and “transferring” for transferring bitmap data of the character which is generated by the fill-in painting. A technique for executing these processing steps in parallel and to carry out these processing steps at a high speed is known. For example, JP-UM-A-5-090583 discloses a technique by which a dedicated module performs the “contour drawing” and “fill-in painting” while a CPU (Central Processing Unit) performs the “transferring”.
According to the technique described in the above publication, a large amount of data is read by the CPU while the CPU performs the “transferring”. Therefore, most of the buses connected to the CPU are occupied by data being transferred. If any module attempts the “contour drawing” and “fill-in painting” during the “transferring”, data required for the “contour drawing” and “fill-in painting” cannot be supplied to the bus. This gives rise to a problem that an increase in the speed of processing cannot be achieved.